SIM card in padded envelope. Recorded/Special delivery. Or 'envelope service from a courier.
Adding: the SIM will get your number live again but, nowadays, data is stored in the phone due to the memory requirements. So, if you are not going back to HKG soon, you may need to find alternative ways of getting the data. This can be if you have online back up
pr the phone is made live with a PAYG SIm and then backed up so that it can be sent to you.